<template>
  <view class="content">

    <scroll-view scroll-y class="left-aside">
      <view v-for="item in flist" :key="item.id" class="f-item b-b" :class="{ active: item.id == currentId }" @click="tabtap(item)">{{ item.name }}</view>
    </scroll-view>

    <scroll-view scroll-with-animation scroll-y class="right-aside" @scroll="asideScroll" :scroll-top="tabScrollTop">
      <view v-for="item in slist" :key="item.id" class="s-list" :id="'main-' + item.id">
        <text class="s-item">{{ item.name }}</text>
        <view class="t-list">
          <view @click="navToList(item.id, titem.id)" v-if="titem.parentId === item.id" class="t-item" v-for="titem in tlist" :key="titem.id">
            <image :src="titem.iconUrl"></image>
            <text>{{ titem.name }}</text>
          </view>
        </view>
      </view>
    </scroll-view>

  </view>
</template>

<script>
import { list} from "../../api/product/category";

export default {
  data() {
    return {
      sizeCalcState: false,
      tabScrollTop: 0,
      currentId: 0,
      flist: [],
      slist: [],
      tlist: []
    };
  },
  onLoad() {
    this.loadData();
  },
  methods: {
    async loadData() {
      list().then(response => {
        const categoryList = response.data;
        categoryList.forEach(first => {
          this.flist.push(first);
          if (first.children) {
            first.children.forEach(second => {
              this.slist.push(second);
              if (second.children) {
                second.children.forEach(third => {
                  this.tlist.push(third);
                });
              }
            });
          }
        });
        // 排序
        this.flist.sort(function(a, b) {
          return a.id - b.id;
        });

        this.slist.sort(function(a, b) {
          if (a.parentId == b.parentId) {
            return a.id - b.id;
          } else {
            return a.parentId - b.parentId;
          }
        });

        this.tlist.sort(function(a, b) {
          if (a.parentId == b.parentId) {
            return a.id - b.id;
          } else {
            return a.parentId - b.parentId;
          }
        });

        this.currentId = this.flist[0].id;
      });
    },
    //一级分类点击
    tabtap(item) {
      console.log('item:',item)
      if (!this.sizeCalcState) {
        this.calcSize();
      }
      this.currentId = item.id;
      let index = this.slist.findIndex(sitem => sitem.parentId == item.id);
      this.tabScrollTop = this.slist[index].top;
    },
    //右侧栏滚动
    asideScroll(e) {
      if (!this.sizeCalcState) {
        this.calcSize();
      }
      let scrollTop = e.detail.scrollTop;
      let tabs = this.slist.filter(item => item.top <= scrollTop).reverse();
      if (tabs.length > 0) {
        this.currentId = tabs[0].parentId;
      }
    },
    //计算右侧栏每个tab的高度等信息
    calcSize() {
      let h = 0;
      this.slist.forEach(item => {
        let view = uni.createSelectorQuery().select('#main-' + item.id);
        view.fields(
            {size: true},
            data => {
              item.top = h;
              h += data.height;
              item.bottom = h;
            }
        ).exec();
      });
      this.sizeCalcState = true;
    },
    navToList(sid, tid) {
      uni.navigateTo({
        url: `/pages/product/list?fid=${this.currentId}&sid=${sid}&tid=${tid}`
      });
    }
  }
};
</script>

<style lang="scss">
page,
.content {
  height: 100%;
  background-color: #f8f8f8;
}

.content {
  display: flex;
}
.left-aside {
  flex-shrink: 0;
  width: 200upx;
  height: 100%;
  background-color: #fff;
}
.f-item {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  height: 100upx;
  font-size: 28upx;
  color: $font-color-base;
  position: relative;
  &.active {
    color: $base-color;
    background: #f8f8f8;
    &:before {
      content: '';
      position: absolute;
      left: 0;
      top: 50%;
      transform: translateY(-50%);
      height: 36upx;
      width: 8upx;
      background-color: $base-color;
      border-radius: 0 4px 4px 0;
      opacity: 0.8;
    }
  }
}

.right-aside {
  flex: 1;
  overflow: hidden;
  padding-left: 20upx;
}
.s-item {
  display: flex;
  align-items: center;
  height: 70upx;
  padding-top: 8upx;
  font-size: 28upx;
  color: $font-color-dark;
}
.t-list {
  display: flex;
  flex-wrap: wrap;
  width: 100%;
  background: #fff;
  padding-top: 12upx;
  &:after {
    content: '';
    flex: 99;
    height: 0;
  }
}
.t-item {
  flex-shrink: 0;
  display: flex;
  justify-content: center;
  align-items: center;
  flex-direction: column;
  width: 176upx;
  font-size: 26upx;
  color: #666;
  padding-bottom: 20upx;

  image {
    width: 140upx;
    height: 140upx;
  }
}
</style>
